Malicious ONBUILD demo

Demo resources to show how ONBUILD instruction could be used to build malicious Docker images.

Go demo binary build with saschagrunert/demo framkework.

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Demo info

• Malicious docker image:

  • containers/malicious

• SFTP:

  • Uses mayth/simple-upload-server docker image

• Innocent docker images:

  • containers/inno, containers/inno-2, containers/inno-3

• Go binary:

  • Files: main.go, go.mod, go.sum and pkg/*.go
  • Binary already build: malicious-onbuild-demo

    ➜ ./malicious-onbuild-demo --h
    NAME:
      Malicious ONBUILD demo - Malicious ONBUILD instruction demo
    
    USAGE:
      malicious-onbuild-demo [global options] command [command options] [arguments...]
    
    AUTHOR:
      Andoni Alonso <[email protected]>
    
    COMMANDS:
      help, h  Shows a list of commands or help for one command
    
    GLOBAL OPTIONS:
      --all, -l                     run all demos (default: false)
      --auto, -a                    run the demo in automatic mode, where every step gets executed automatically (default: false)
      --auto-timeout auto, -t auto  the timeout to be waited when auto is enabled (default: 3s)
      --continuously, -c            run the demos continuously without any end (default: false)
      --hide-descriptions, -d       hide descriptions between the steps (default: false)
      --immediate, -i               immediately output without the typewriter animation (default: false)
      --skip-steps value, -s value  skip the amount of initial steps within the demo (default: 0)
      -0, --onbuild_basic           Explain what is ONBUILD instruction (default: false)
      -1, --show_malicious          Show onbuild_malicious container (default: false)
      -2, --use_malicious_1         Use onbuild_malicious container I (default: false)
      -3, --what_happened           What happened using onbuild_malicious container (default: false)
      -4, --use_malicious_2         Use onbuild_malicious container II (default: false)
      -5, --conclusions             Conclusions about ONBUILD instruction (default: false)
      --help, -h                    show help (default: false)
    

If you want to play without the demo binary you can use check the Makefile:

➜ make
Available rules:

build-go            Build go binary
build-innocent      Build client image from local malicious image
build-innocent-2    Build client from local malicious image + use.dockerignore
build-innocent-3    Build client from Dockerhub malicious image + use.dockerignore
build-malicious     Build local malicious image
open-upload         Shows SFTP content
run                 Run all demo steps
run-fast            Run all demo steps (without typewritter animation)
server-up           Start SFTP local server

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More info

• ONBUILD docker docs.
• ONBUILD in buildah images.
• Article from redlock.io that mention malicious ONBUILD images.
• [ES]Talk: Docker Layers, Dive In @ HacknightVLC